1. Field of the Invention
The present invention relates to reclining devices for seats, particularly for automotive seats.
2. Description of the Prior Art
Hitherto, various kinds of reclining devices have been proposed and put into practical use particularly in the field of automotive seats. As is known, the reclining device is a device for adjusting the angular position of a seatback relative to a seat cushion to provide a seat occupant with a comfortable sitting posture. Most of the conventional reclining devices are of a type which comprises a toothed lock plate which is mounted to a hinge arm of the seatback, and a pawl-mounted lock lever which is pivotally connected to a base member on the seat cushion, wherein upon position adjustment of the seatback, the pawl of the lock lever is latchingly engaged with one or some of the teeth of the lock plate.
In the reclining device of this type, a fairly strong spring is incorporated with the lock lever in order to assure the latched engagement between the lock lever and the lock plate even when the seat is subjected to a severe treatment. In fact, when, due to sudden sitting of a person on the seat, a marked load is suddenly applied to the seatback, the lock lever is applied with a big force in a direction to break the latched engagement with the lock plate. In order to deal with this undesirable phenomenon, such a strong spring is employed.
However, usage of such a strong biasing spring, in turn, brings about a difficulty in manipulating an actuating handle incorporated with the lock lever. In fact, the manipulation of the handle for the purpose of cancelling the latched engagement between the lock lever and the lock plate should be carried out against a big force produced by the spring.